A flexible-rigid circuit board composite represents a hybrid composite of circuit boards, also referred to as PCB (printed circuit board), in which flexible and rigid circuit boards are connected to one another to form a single circuit board composite. The various layers of a multilayer flexible-rigid circuit board composite are typically connected via metallically coated through openings.
U.S. Publication No. 2004/0118595 discloses a circuit board composite made of flexible and rigid circuit boards, in which at least one flexible circuit board is arranged on at least one rigid circuit board. For this purpose, the rigid circuit board intentionally has a structural weak point at a defined position. The structural weak point is used for the purpose of intentionally breaking off the rigid circuit board and connecting the fracture edges to the flexible circuit board.
A method for producing a rigid-flexible printed circuit board composite (PCB) from rigid and flexible circuit boards is disclosed in U.S. Pat. No. 7,690,104. The circuit boards are placed on a carrier, on which the circuit boards are aligned to one another so that the bond regions of the flexible circuit board overlap with the bond regions of the rigid circuit board. The aligned circuit boards are subsequently pressed together and sent through a reflow furnace, with the solder on the circuit boards melting and, after the solidification, the circuit boards and electrical components located thereon being mechanically and electrically connected.
The fastening of flexible connecting bridges to rigid or stiffened PCBs is typically performed to utilize the advantages of packaging, i.e., construction and connection technology, with flexible substrates in costly electronic components, in which significantly more cost-effective rigid circuit boards are used for reasons of cost. Such a connection step, typically by means of hot bar soldering or laser soldering, is performed in discrete steps, circuit by circuit.
The additional handling and positioning of isolated flexible connecting bridges and PCB structures is difficult to automate, which results in high production costs and decreases the cycle time for the production of the flexible connections. In small PCB structures, as are used in medical implants, these problems are increased still further.
The present invention is directed toward overcoming one or more of the above-identified problems.
The present invention is based on an object of providing a flexible circuit board which allows extensive automation of the production method of a flexible-rigid circuit board composite.
A further object is the provision of a flexible circuit board arrangement having at least one flexible circuit board for a flexible-rigid circuit board composite, which allows extensive automation of the production method of a flexible-rigid circuit board composite.
Yet a further object is to provide a flexible-rigid circuit board composite which is producible cost-effectively with high precision and is suitable, in particular, for electronics in medical implants.
Still a further object comprises providing an improved method for producing a flexible-rigid circuit board composite.